The present invention relates generally to a system for dispensing a fuel such as gasoline into the fuel tank of a motor vehicle. More particularly the present invention pertains to such a dispensing system wherein the customer has an option to automatically have an additive dispensed along with the gasoline and wherein the price of the additive is automatically computed into the displayed sales price at the pump.
Additives to gasoline to perform various functions such as cleaning carburetors, valves, etc. are well known in the art. These additives are commonly sold in the prior art in small containers. A disadvantage with this method of purchasing additives is that the addition of the additive to the gasoline is often cumbersome, and frequently results in quantities of the additive being spilled rather than being directed into the fillpipe of the motor vehicle.
It is also known to inject an additive into a main stream of fluid. U.S. 4,007,755, for example, discloses a system for injecting a predetermined amount of additive fluid to a main stream in such a way as to keep the additive concentration in the main stream constant. Also, it is known to optionally blend motor fuels of different octanes as disclosed in U.S. 3,934,756. In the disclosure of this patent a mechanical system using a double-acting cam is employed to continuously blend fuels from two storage tanks.
In accordance with a disclosed embodiment, a system is disclosed for conveniently dispensing an additive along with fuel. The system is for use in conjunction with a typical prior art system for dispensing fuel having, an underground storage tank for the fuel, a pump for pumping the fuel from the underground tank during a dispensing operation, a meter for measuring the quantity of fuel dispensed, a computer for computing the cost for the quantity of fuel dispensed, and a display for displaying the quantity and cost of fuel dispensed. The disclosed embodiment allows a customer the option of having an additive automatically added to the dispensed fuel and the price of the additive automatically computed into the sale. The disclosed embodiment comprises a storage reservoir for the additive which is separate from the underground storage tank, an additional pump activated when desired, by fuel flow and coupled to the storage reservoir for pumping slugs of additive as required to the gasoline dispensing unit during a dispensing operation, an additional meter for metering the quantity of additive dispensed, a coupling means for coupling the output of the additional meter to the display to automatically add the cost of the dispensed additive to the displayed cost, and a selector means for selectively allowing, at the option of the customer, additive to be dispensed or not along with the dispensed fuel.
Further, in the disclosed embodiment the display comprises an electronic display responsive to electrical pulses to display the cost and quantity of the dispensed product. The system produces electrical pulses indicative of the cost of the fuel dispensed and electrical pulses indicative of the cost of the additive dispensed, and the electrical pulses indicative of the cost of additive are coupled to the display for inclusion with the electrical pulses indicative of the cost of fuel to determine the displayed cost. Further, electrical pulses indicative of the quantity of fuel dispensed are produced, and these electrical pulses are coupled to the additional pump which pumps additive in a pulsed fashion (i.e. not continuously) in response to these electrical pulses. This results in the additive being proportionately blended with the dispensed fuel. Further, in the disclosed embodiment the selector means is simply a switch for selectively coupling, or not, the electrical pulses indicative of quantity of fuel dispensed to the additional pump for the additive and for optionally coupling the electrical pulses indicative of the quantity of fuel dispensed to the second pump. Also, in the disclosed embodiment the switch is automatically reset to an open position before a new dispensing operation is started. Also, in the disclosed embodiment the storage reservoir is preferably located within the dispensing console.